Which compound would you expect to have the highest melting point?

BeO

MgO

CaO

SrO

2 answers

The one with the greater electronegativity difference. Electronegativity increase up and to the right of the periodic table, so the atom that is attached to O with smallest electronegativity should be the one with the highest melting point. But I am not 100% positive.

SrO is my choice.
devron you're wrong mate
because Be has the highest electronegativity difference, it will form the most polar molecule meaning the permanent diploe-dipole forces will be the strongest, therefore the highest melting point